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linux/drivers/rtc/rtc-mxc_v2.c
Uwe Kleine-König 153f56f9ce rtc: mxc_v2: Convert to platform remove callback returning void 
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230304133028.2135435-21-u.kleine-koenig@pengutronix.de
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2023-03-17 23:03:17 +01:00

392 lines
9.9 KiB
C
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// SPDX-License-Identifier: GPL-2.0
/*
* Real Time Clock (RTC) Driver for i.MX53
* Copyright (c) 2004-2011 Freescale Semiconductor, Inc.
* Copyright (c) 2017 Beckhoff Automation GmbH & Co. KG
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/pm_wakeirq.h>
#include <linux/rtc.h>
#define SRTC_LPPDR_INIT 0x41736166 /* init for glitch detect */
#define SRTC_LPCR_EN_LP BIT(3) /* lp enable */
#define SRTC_LPCR_WAE BIT(4) /* lp wakeup alarm enable */
#define SRTC_LPCR_ALP BIT(7) /* lp alarm flag */
#define SRTC_LPCR_NSA BIT(11) /* lp non secure access */
#define SRTC_LPCR_NVE BIT(14) /* lp non valid state exit bit */
#define SRTC_LPCR_IE BIT(15) /* lp init state exit bit */
#define SRTC_LPSR_ALP BIT(3) /* lp alarm flag */
#define SRTC_LPSR_NVES BIT(14) /* lp non-valid state exit status */
#define SRTC_LPSR_IES BIT(15) /* lp init state exit status */
#define SRTC_LPSCMR 0x00 /* LP Secure Counter MSB Reg */
#define SRTC_LPSCLR 0x04 /* LP Secure Counter LSB Reg */
#define SRTC_LPSAR 0x08 /* LP Secure Alarm Reg */
#define SRTC_LPCR 0x10 /* LP Control Reg */
#define SRTC_LPSR 0x14 /* LP Status Reg */
#define SRTC_LPPDR 0x18 /* LP Power Supply Glitch Detector Reg */
/* max. number of retries to read registers, 120 was max during test */
#define REG_READ_TIMEOUT 2000
struct mxc_rtc_data {
struct rtc_device *rtc;
void __iomem *ioaddr;
struct clk *clk;
spinlock_t lock; /* protects register access */
int irq;
};
/*
* This function does write synchronization for writes to the lp srtc block.
* To take care of the asynchronous CKIL clock, all writes from the IP domain
* will be synchronized to the CKIL domain.
* The caller should hold the pdata->lock
*/
static void mxc_rtc_sync_lp_locked(struct device *dev, void __iomem *ioaddr)
{
unsigned int i;
/* Wait for 3 CKIL cycles */
for (i = 0; i < 3; i++) {
const u32 count = readl(ioaddr + SRTC_LPSCLR);
unsigned int timeout = REG_READ_TIMEOUT;
while ((readl(ioaddr + SRTC_LPSCLR)) == count) {
if (!--timeout) {
dev_err_once(dev, "SRTC_LPSCLR stuck! Check your hw.\n");
return;
}
}
}
}
/* This function is the RTC interrupt service routine. */
static irqreturn_t mxc_rtc_interrupt(int irq, void *dev_id)
{
struct device *dev = dev_id;
struct mxc_rtc_data *pdata = dev_get_drvdata(dev);
void __iomem *ioaddr = pdata->ioaddr;
u32 lp_status;
u32 lp_cr;
spin_lock(&pdata->lock);
if (clk_enable(pdata->clk)) {
spin_unlock(&pdata->lock);
return IRQ_NONE;
}
lp_status = readl(ioaddr + SRTC_LPSR);
lp_cr = readl(ioaddr + SRTC_LPCR);
/* update irq data & counter */
if (lp_status & SRTC_LPSR_ALP) {
if (lp_cr & SRTC_LPCR_ALP)
rtc_update_irq(pdata->rtc, 1, RTC_AF | RTC_IRQF);
/* disable further lp alarm interrupts */
lp_cr &= ~(SRTC_LPCR_ALP | SRTC_LPCR_WAE);
}
/* Update interrupt enables */
writel(lp_cr, ioaddr + SRTC_LPCR);
/* clear interrupt status */
writel(lp_status, ioaddr + SRTC_LPSR);
mxc_rtc_sync_lp_locked(dev, ioaddr);
clk_disable(pdata->clk);
spin_unlock(&pdata->lock);
return IRQ_HANDLED;
}
/*
* Enable clk and aquire spinlock
* @return 0 if successful; non-zero otherwise.
*/
static int mxc_rtc_lock(struct mxc_rtc_data *const pdata)
{
int ret;
spin_lock_irq(&pdata->lock);
ret = clk_enable(pdata->clk);
if (ret) {
spin_unlock_irq(&pdata->lock);
return ret;
}
return 0;
}
static int mxc_rtc_unlock(struct mxc_rtc_data *const pdata)
{
clk_disable(pdata->clk);
spin_unlock_irq(&pdata->lock);
return 0;
}
/*
* This function reads the current RTC time into tm in Gregorian date.
*
* @param tm contains the RTC time value upon return
*
* @return 0 if successful; non-zero otherwise.
*/
static int mxc_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct mxc_rtc_data *pdata = dev_get_drvdata(dev);
const int clk_failed = clk_enable(pdata->clk);
if (!clk_failed) {
const time64_t now = readl(pdata->ioaddr + SRTC_LPSCMR);
rtc_time64_to_tm(now, tm);
clk_disable(pdata->clk);
return 0;
}
return clk_failed;
}
/*
* This function sets the internal RTC time based on tm in Gregorian date.
*
* @param tm the time value to be set in the RTC
*
* @return 0 if successful; non-zero otherwise.
*/
static int mxc_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct mxc_rtc_data *pdata = dev_get_drvdata(dev);
time64_t time = rtc_tm_to_time64(tm);
int ret;
ret = mxc_rtc_lock(pdata);
if (ret)
return ret;
writel(time, pdata->ioaddr + SRTC_LPSCMR);
mxc_rtc_sync_lp_locked(dev, pdata->ioaddr);
return mxc_rtc_unlock(pdata);
}
/*
* This function reads the current alarm value into the passed in \b alrm
* argument. It updates the \b alrm's pending field value based on the whether
* an alarm interrupt occurs or not.
*
* @param alrm contains the RTC alarm value upon return
*
* @return 0 if successful; non-zero otherwise.
*/
static int mxc_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct mxc_rtc_data *pdata = dev_get_drvdata(dev);
void __iomem *ioaddr = pdata->ioaddr;
int ret;
ret = mxc_rtc_lock(pdata);
if (ret)
return ret;
rtc_time64_to_tm(readl(ioaddr + SRTC_LPSAR), &alrm->time);
alrm->pending = !!(readl(ioaddr + SRTC_LPSR) & SRTC_LPSR_ALP);
return mxc_rtc_unlock(pdata);
}
/*
* Enable/Disable alarm interrupt
* The caller should hold the pdata->lock
*/
static void mxc_rtc_alarm_irq_enable_locked(struct mxc_rtc_data *pdata,
unsigned int enable)
{
u32 lp_cr = readl(pdata->ioaddr + SRTC_LPCR);
if (enable)
lp_cr |= (SRTC_LPCR_ALP | SRTC_LPCR_WAE);
else
lp_cr &= ~(SRTC_LPCR_ALP | SRTC_LPCR_WAE);
writel(lp_cr, pdata->ioaddr + SRTC_LPCR);
}
static int mxc_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
{
struct mxc_rtc_data *pdata = dev_get_drvdata(dev);
int ret = mxc_rtc_lock(pdata);
if (ret)
return ret;
mxc_rtc_alarm_irq_enable_locked(pdata, enable);
return mxc_rtc_unlock(pdata);
}
/*
* This function sets the RTC alarm based on passed in alrm.
*
* @param alrm the alarm value to be set in the RTC
*
* @return 0 if successful; non-zero otherwise.
*/
static int mxc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
const time64_t time = rtc_tm_to_time64(&alrm->time);
struct mxc_rtc_data *pdata = dev_get_drvdata(dev);
int ret = mxc_rtc_lock(pdata);
if (ret)
return ret;
writel((u32)time, pdata->ioaddr + SRTC_LPSAR);
/* clear alarm interrupt status bit */
writel(SRTC_LPSR_ALP, pdata->ioaddr + SRTC_LPSR);
mxc_rtc_sync_lp_locked(dev, pdata->ioaddr);
mxc_rtc_alarm_irq_enable_locked(pdata, alrm->enabled);
mxc_rtc_sync_lp_locked(dev, pdata->ioaddr);
mxc_rtc_unlock(pdata);
return ret;
}
static const struct rtc_class_ops mxc_rtc_ops = {
.read_time = mxc_rtc_read_time,
.set_time = mxc_rtc_set_time,
.read_alarm = mxc_rtc_read_alarm,
.set_alarm = mxc_rtc_set_alarm,
.alarm_irq_enable = mxc_rtc_alarm_irq_enable,
};
static int mxc_rtc_wait_for_flag(void __iomem *ioaddr, int flag)
{
unsigned int timeout = REG_READ_TIMEOUT;
while (!(readl(ioaddr) & flag)) {
if (!--timeout)
return -EBUSY;
}
return 0;
}
static int mxc_rtc_probe(struct platform_device *pdev)
{
struct mxc_rtc_data *pdata;
void __iomem *ioaddr;
int ret = 0;
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
pdata->ioaddr = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(pdata->ioaddr))
return PTR_ERR(pdata->ioaddr);
ioaddr = pdata->ioaddr;
pdata->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(pdata->clk)) {
dev_err(&pdev->dev, "unable to get rtc clock!\n");
return PTR_ERR(pdata->clk);
}
spin_lock_init(&pdata->lock);
pdata->irq = platform_get_irq(pdev, 0);
if (pdata->irq < 0)
return pdata->irq;
device_init_wakeup(&pdev->dev, 1);
ret = dev_pm_set_wake_irq(&pdev->dev, pdata->irq);
if (ret)
dev_err(&pdev->dev, "failed to enable irq wake\n");
ret = clk_prepare_enable(pdata->clk);
if (ret)
return ret;
/* initialize glitch detect */
writel(SRTC_LPPDR_INIT, ioaddr + SRTC_LPPDR);
/* clear lp interrupt status */
writel(0xFFFFFFFF, ioaddr + SRTC_LPSR);
/* move out of init state */
writel((SRTC_LPCR_IE | SRTC_LPCR_NSA), ioaddr + SRTC_LPCR);
ret = mxc_rtc_wait_for_flag(ioaddr + SRTC_LPSR, SRTC_LPSR_IES);
if (ret) {
dev_err(&pdev->dev, "Timeout waiting for SRTC_LPSR_IES\n");
clk_disable_unprepare(pdata->clk);
return ret;
}
/* move out of non-valid state */
writel((SRTC_LPCR_IE | SRTC_LPCR_NVE | SRTC_LPCR_NSA |
SRTC_LPCR_EN_LP), ioaddr + SRTC_LPCR);
ret = mxc_rtc_wait_for_flag(ioaddr + SRTC_LPSR, SRTC_LPSR_NVES);
if (ret) {
dev_err(&pdev->dev, "Timeout waiting for SRTC_LPSR_NVES\n");
clk_disable_unprepare(pdata->clk);
return ret;
}
pdata->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(pdata->rtc)) {
clk_disable_unprepare(pdata->clk);
return PTR_ERR(pdata->rtc);
}
pdata->rtc->ops = &mxc_rtc_ops;
pdata->rtc->range_max = U32_MAX;
clk_disable(pdata->clk);
platform_set_drvdata(pdev, pdata);
ret =
devm_request_irq(&pdev->dev, pdata->irq, mxc_rtc_interrupt, 0,
pdev->name, &pdev->dev);
if (ret < 0) {
dev_err(&pdev->dev, "interrupt not available.\n");
clk_unprepare(pdata->clk);
return ret;
}
ret = devm_rtc_register_device(pdata->rtc);
if (ret < 0)
clk_unprepare(pdata->clk);
return ret;
}
static void mxc_rtc_remove(struct platform_device *pdev)
{
struct mxc_rtc_data *pdata = platform_get_drvdata(pdev);
clk_disable_unprepare(pdata->clk);
}
static const struct of_device_id mxc_ids[] = {
{ .compatible = "fsl,imx53-rtc", },
{}
};
MODULE_DEVICE_TABLE(of, mxc_ids);
static struct platform_driver mxc_rtc_driver = {
.driver = {
.name = "mxc_rtc_v2",
.of_match_table = mxc_ids,
},
.probe = mxc_rtc_probe,
.remove_new = mxc_rtc_remove,
};
module_platform_driver(mxc_rtc_driver);
MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("Real Time Clock (RTC) Driver for i.MX53");
MODULE_LICENSE("GPL");
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